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| Titel |
Adjoint inversion modeling of Asian dust emission using lidar observations |
| VerfasserIn |
K. Yumimoto, I. Uno, N. Sugimoto, A. Shimizu, Z. Liu, D. M. Winker |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 8, no. 11 ; Nr. 8, no. 11 (2008-06-05), S.2869-2884 |
| Datensatznummer |
250006180
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| Publikation (Nr.) |
 copernicus.org/acp-8-2869-2008.pdf |
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| Zusammenfassung |
| A four-dimensional variational (4D-Var) data assimilation system for a
regional dust model (RAMS/CFORS-4DVAR; RC4) is applied to an adjoint
inversion of a heavy dust event over eastern Asia during 20 March–4 April
2007. The vertical profiles of the dust extinction coefficients derived from
NIES Lidar network are directly assimilated, with validation using
observation data. Two experiments assess impacts of observation site
selection: Experiment A uses five Japanese observation sites located downwind
of dust source regions; Experiment B uses these and two other sites near
source regions. Assimilation improves the modeled dust extinction
coefficients. Experiment A and Experiment B assimilation results are mutually
consistent, indicating that observations of Experiment A distributed over
Japan can provide comprehensive information related to dust emission
inversion. Time series data of dust AOT calculated using modeled and Lidar
dust extinction coefficients improve the model results. At Seoul, Matsue, and
Toyama, assimilation reduces the root mean square differences of dust AOT by
35–40%. However, at Beijing and Tsukuba, the RMS differences degrade
because of fewer observations during the heavy dust event. Vertical profiles
of the dust layer observed by CALIPSO are compared with assimilation results.
The dense dust layer was trapped at potential temperatures (θ) of
280–300 K and was higher toward the north; the model reproduces those
characteristics well. Latitudinal distributions of modeled dust AOT along the
CALIPSO orbit paths agree well with those of CALIPSO dust AOT, OMI AI, and
MODIS coarse-mode AOT, capturing the latitude at which AOTs and AI have high
values. Assimilation results show increased dust emissions over the Gobi
Desert and Mongolia; especially for 29–30 March, emission flux is about 10
times greater. Strong dust uplift fluxes over the Gobi Desert and Mongolia
cause the heavy dust event. Total optimized dust emissions are 57.9 Tg
(Experiment A; 57.8% larger than before assimilation) and 56.3 Tg
(Experiment B; 53.4% larger). |
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